LANSING — When even the slightest amount of mercury enters a fish’s body, it can begin a long cycle that ends in disaster for aquatic wildlife and health concerns for humans, experts say.

That’s because mercury, an element often produced as a byproduct of mining and fossil fuel production, never breaks down or leaves an organism’s body. Instead, it continues to be passed along as animals eat and get eaten.

“The material concentrates even more,” said Megan Tinsley, the water policy director at the Michigan Environmental Council. “As it moves up the food chain, you can have organisms holding higher and higher levels of those chemicals.”

That results in mercury-contaminated wildlife and do-not-eat advisories for humans.

Although mercury is especially infamous for being passed along the food chain, it isn’t the only toxic chemical that triggers that process — something scientists call bioaccumulation.

It’s one of 22 chemicals that the Department of Environment, Great Lakes and Energy, or EGLE, recognizes as “bioaccumulative chemicals of concern,” or BCCs. Other chemicals include a form of the once-popular insecticide DDT and polychlorinated biphenyls, or PCBs, a compound that was used in manufacturing and has been linked to cancer.

Many of those chemicals pollute the environment through run-off or chemical leaks, said Kevin Cox, the department’s water toxics unit supervisor..

“The presence of these chemicals in the environment can impact the health of both aquatic organisms as well as humans who become exposed through consuming fish or ingesting contaminated surface waters,” Cox said.

But the department’s current list of bioaccumulative chemicals — which Tinsley says is crucial to public understanding of which substances are especially harmful to human health — hasn’t been updated in nearly 20 years, despite updated science.

That’s because EGLE legally can’t make additional rules on water quality regulation. A provision in the state’s Natural Resources and Environmental Protection Act prohibits the department from issuing additional water regulation rules after Dec. 31, 2006.